Pages is not updating documents in the cloud when edited on Mac

I edited a pages document – which was created on my iPhone – on my Mac, but it did not update. It seemed to be stuck on 6.8MB out of 12.6MB. So I deleted it, and reloaded it from my desktop, and now it is stuck on "Waiting" with a little cloud symbol beside it.

The document has appeared on my iPhone again, but it won't download (because it hasn't been uploaded), and it can't be viewed.

Does anybody know how to fix this problem?